Digger



Dec. 21, 1943. G. STRAIN DIGGER Filed Aug. 4, 1940 5 Sheets-Sheet 1 INVENTOR. ficzesnr G. She/10v ATTORNEK Dec."21, 1943. H. G. STRAIN 2,337,133

DIGGER Filed Aug.4, 1940 5 Sheets-Sheet 3 a4 FJ Eu? A Tron/vs! Patented Dec. 21, 1943 UNITED assign STATES PATENT OFFICE BIGGER Appiication August 4, 1940, Serial No. 351,390

9 Claims.

This invention relates to digging equipment, and particularly to a digger for sampling purposes. v

In testing properties for mining, it is necessary to take samples of the earth deposits for analysis. This analysis will be carried out separately for the different vertical levels thruout the properties, since different strata will vary in mineral content. For this purpose, various types of machines have been used. In some cases, a hand operation is sufficient. Where greater depth is required, earth augers, or screw type diggers have been used. These are open to objection, however, in that they are very slow in operation and are easily damaged by large rocks or small boulders in their path.

The present invention is designed to avoid such difficulties, and comprises, in brief, a power driven bucket digger of the clamshell type which is so adjusted as to dig a square hole of the same outer dimensions as the bucket, to any desired depth, and to permit very accurate sampling of the material dug.

Portability is secured by mounting the entire unit on a special frame built onto a truck chassis.

The unit includes a motor, which may be of con ventional internal combustion type or its equivalent. The motor drives a winch, which is controlled by an operator thru conventional hand levers and foot brakes, and actuates the bucket.

The unit includes a vertical guide in which the mast, or vertical column to which the bucket is attached, may slide. The mast must be of sufiicient length to carry to the bottom of the desired hole, and the guides must be proportioned accordingly. 7

This digger is designed primarily for testing areas which will be surface mined by placer or strip methods, and hence ordinarily it is not necessary to dig below 50 feet, but greater depths can be handled successfully. The depth of the bucket is indicated by markings on the mast which may be read opposite the level of the ground.

In use, the operator raises the mast with the bucket open over the intended site by engaging the holding line drum on his winch. He then releases the holding line and forces the mast and bucket downward by means of a crowd line connected to another drum of the winch. The drive from the winch, plus the weight of the mast and bucket, forces or crowds the teeth of the latter into the ground. If it is exceptionally hard, repeated blows may be necessary. When the bucket has penetrated a desired distance, a closing line drum is connected to draw the bucket into closed position, after which it may be lifted out of the hole by again engaging the holding line drum.

A small cart is used to take away the earth from the loaded bucket, which is released by disengaging the closing line drum. The discharged material is stored in separate piles arranged in a row, so that the character of successively deeper strata may be observed and the ore analyzed for the diiferent levels.

The weight of the closing elements is so distributed that the bucket normally stays open and ready to deliver a digging blow unless the 010sing drum is engaged. A brake is provided to control the crowd and closing drum action.

More even digging action is obtained by the use of staggered teeth on the bucket shells which interlock when the shells are closed, and by making the bucket rotatable about a vertical axis. In this way, comparatively large rocks and other obstructions may be loosened, turning the bucket and attacking them from diiferent angles.

The turning also insures a square hole with the sides more even and less likely to cave in, since the digging action of the teeth is more uniform than that of the bucket sides. With this method, I have consistently been able to dig from 20 to 40 feet of test hole per hour, removing approximately 1 cubic foot of earth at each bite of the bucket.

The objects of my invention thus include providing a more rapid and efiicient core digger for sampling purposes:

The elimination of caved-in sections of test holes;

Better analyses by procuring more extensive samples;

Elimination of troublesome rocks and obstructions which seriously interfere with auger-type core samplers;

The application of power to core sampling; and

Providing a power digger which may be moved quickly from place to place.

The invention further resides in the combination, construction and arrangement of parts illustrated in the accompanying drawings and while there is shown therein a preferred embodiment, it is to be understood that the same is capable of further modification and change and comprehends other details and constructions without departing from the spirit or the scope of the present invention and the appended claims.

The invention has been illustrated in the drawings, in which:

Fig. 1 is a side View of my device installed on a truck, and showing a preferred form of dump cart used therewith;

Fig, 2 is a side view of the mast and the winch mechanisms taken from the right side of the truck;

Fig. 3 is a side View of the winch drums and their controlling levers, taken from the left side of the truck;

Fig. 4 is a fragmentary top view of the winch mechanism of Fig. 3;

Fig. 5 is a view of the mast and bucket from the rear of the truck;

Fig. 6 is a sectional view of the mast and supporting guides, taken along line 6-6 of Fig. 5;

Fig. 7 is a top sectional schematic view of the bucket, taken along line l-'i of Fig. 5;

Fig. 8 is a schematic sectional view of the bucket and the associated closing mechanism, showing the bucket in closed position;

Fig. 9 is a view, partially in section, of a portion of the bucket and closing mechanism of Fig. 8, taken in open position; and

Fig. 10 is a top sectional view of the mast and crowd block, taken along line lib-ii) of Fig. 9.

Referring now to the figures for a detailed description of a preferred form of the invention:

In Fig. 1, there is shown the digging machine of the present invention mounted as a portable unit on a motor truck I. On the truck I, which must be of substantial construction to withstand the strains of travel and of operation, is secured a frame 2 of heavy channel iron sections. This frame is designed to secure together a prime mover 4, a winch 5 actuated thereby, and the mast guide 6 in which mast 1 slides during operation of bucket 9. In the Fig. l, the machine is shown in its vertical, or digging, position, with the hole It! indicated in the ground beneath. There is also shown a small dumpcart ll in position over the hole E3 to receive the discharged earth when bucket 9 is opened in the elevated position shown. Further reference will be made hereafter to the construction of bucket H and its special function in connection with testing of ore-bearing samples.

When digging a test hole, the operator sits on a seat l2 facing the rear of the truck. The seat i2 is located so that the operator can watch the bucket and observe his progress during the digging operation. Hand levers M areconveniently located to operate the. three component drums of the winch 5, which will be explained in detail below, and foot brakes l5 are provided for control of the crowd and closing drums of winch 5.

When the entire unit is to be moved to a new location, the truck is put in motion and driven with the mast 1 and mast guide 6 in upright position. If the new location is at a considerable distance, or if overhead clearance is impaired en route, the mast is lowered tothe traveling position shown by the dotted outline in Fig. 1. For this purpose, the mast guide 6 is pivoted, at i6, and by releasing locking bolts H from looking lugs i3 on frame 2, the mast guide 6 and mast i are free to tilt about pivot It to the horizontal traveling position. A block and tackle ii! is fixed to the rear portion of truck I and connected by any suitable means, such as a chain 25, to the bucket 9 to aid in lowering and raising the mast. At the front of the truck, I provide a supporting framework 2| 'on which the upper end of the mast may rest in transit.

Turning now to Figs. 2, 3, and 5, I have shown the framework 2 in fragmentary view from the right, left, and rear, respectively, of theframe in its position relative to the truck 1, which has been omitted from these figures for the sake of clarity.

Power is supplied to the winch 5 from the prime mover 4 by a shaft thru a conventional speed reduction gear 25. The prime mover 4 may be a conventional internal combustion engine, or any equivalent type which will provide adequate power in completely portable form. From the reduction gear 25, a chain drive 2? communicates with a drive sprocket 29 mounted on a shaft 30 journaled thru the winch side plates 3! and 32. Right and left side plates Si and 32 respectively, constitute the framework of the winch d, and the shafts supporting the winch drum are fixed in bores formed therethru by suitable nuts 33 threadably secured thereto and seen in Fig. 4:, Shaft 28 supports the closing line drum 35, shaft 35 supports the crowd line drum 36, and shaft 31 supports the holding line drum 39, the drums being journaled about the fixed shafts. The closing line supplies force to close the bucket, the crowd line transmits the force required to make the bucket dig into the ground; while the holding line keeps the bucket closed while raising the bucket and mast with each bucket load of earth.

Adjacent plate 3!, a drive gear til is fixed to shaft 30, and is engaged by sprockets M, 12, and ill revolving on shafts 32, and 31, respectively, and connected to drums E l, 38, and 39, by means of conventional clutch mechanism 45, i6 and il, respectively. Levers i icontrolling the drums operate by engaging these clutch mechanisms thru appropriate linkages. In Fig. 3, the closing line lever 49 is shown pivotally fixed on a shaft 59 supported by suitable framework 55 and rigidly connected to an intermediate lever 5'2, which in turn is connected by a link 54 to an arm 55 directly actuating the closing drum clutch 45.

The holding line lever 56 and the crowd line lever 51 are pivotally mounted on a shaft 59 fixed in the framework 5!. An intermediate lever 5i) and a link 6| connect to an arm 62 directly actuating the holding line drum clutch i! from holding line lever 56. An intermediate lever 64 and link 65 connect to crowd clutch as thru arm 6%.

A foot brake is provided for the crowd drum and for the holding drum. The holding drum is provided with a brake 68 actuated by a foot pedal 89 thru a tubular shaft lEl journaled thru winch side plate 32. Thru shaft iii, a crowd brake shaft H is inserted from crowd brake pedal 12. Shaft ll controls brake M thru conventional linkages forming a part of the brake 14.

Turning from the winch construction to the mast and mast guides, it will be seen how the winch operator can readily'control the bucket in igging. The mast guides 6 are composed of channel iron sections within which are wooden shoes 35, which conveniently may be formed of long timber sections. Between shoes i5, as shown in Fig. 6, and guided thereby, are channel sections l6 forming the mast sides and connected by a face plate Ti to form the mast unit i} The mast I must be long enough to run up and down against the guide shoes 15 for any depth of hole, and can have additional sections bolted on the top if need arises. The shaft ie on which mast i and guides 6 pivot is held tothe main frame 2 by supporting channel iron columnslSii, reinforced by auxiliary supporting members 8i. Additional auxiliary frame members 82 connect to the top of the winch side plates 3i and 32 and to bearing plates 35. Mast guide bearing plates 85 fit against bearing plates M and are fixed on the mast guides 6 to insure proper alignment of mast, guides, and supporting framework while allowing the tilting of the mast into traveling position. Pulley sheaves are supported by shaft is between channel sections #6 of the mast I and are freely rotatable on shaft I6. A crowd line sheave 88 is provided beneath which the crowd line ill may pass from the crowd drurn 35. Crowd line 3's extends to the top of mast I and is tied thereto at the top by any convenient means. I have shown the crowd line 81 anchored by being passed thru suitable boresSSl in face plate ll and secured by a U-bolt 90. It will be seen from this construction that the operator can apply the full force of his winch motor to driving the mast and bucket into the ground from an elevated position, adding to the blow by the weight of the mast itself.

A holding line sheave BI is provided, over which the holding line 92 from the holding drum 39 is passed. Holding line 92 extends downwardly along mast l and is anchored to face plate ll by a combination 94 of a U-bolt and face plate bores such as that used at the mast top to anchor the crowd line. When the operator applies power to the holding drum as, holding line it raises the entire mast I and bucket 9. The closing line sheave 95, located on shaft It, between sheaves 86 and ill, carries the closing line d from closing drum 34 to a bucket closing sheave E l which is slidable within mast I. Line then passes underneath closing tube sheave ill and upwardly to anchor in face plate ll by means of a U-bolt and face plate bore unit 9%. The operation of the closing drum 3d closes bucket 9, as will be set forth in greater detail hereafter, with particular reference to the deta led showing of Figs. 1, 8, 9, and 10.

The bucket 9 must be capable of being held in open position while it is driven or crowded into the ground, must then be closed to forcibly encompass a bucket-full of the ground being tested, and must be held closed while being raised out of the hole for dumping the load. Finally, the bucket must be rotated about its vertical axis in order to dig the desired square hole and to dislodge diificult rocks in its path.

For these reasons, it is necessary to use a double supporting structure for the bucket, firmly supporting the bucket shells centrally and at their sides. Within and at the bottom of mast E, I fix a tubular guide sleeve I fill having a threaded terminal section lill projecting beneath the mast l. About the projecting portion of sleeve I I position a crowd yoke Hi2, which is rotatable about sleeve Itil, and hold the yoke It2 on sleeve it by means of a lock nut I04 threadably engaging threaded sleeve portion Illl. A washer I85 is set between the crowd yoke Hi2 and lock nut Hil to permit rotation of the former. A crowd collar IE5 is formed on the lower portion of mast 'i to engage the upper surface of crowd yoke i2. Beneath crowd yoke It?! are extended lugs Iii? bored to receive freely shafts I99 carrying bucket legs IIEl. Legs iii are held on shafts I839 by suitable means such as nuts III. To bucket legs I I ll, I connect the bucket shells I I2 by shafts I I4 jcurnaled therein. Bucket end arms H5 are connected to a central shaft H6 housed within a split supporting tube Ill held together by U- bolts H9 and plate lid. The supporting tube I ll is attached securely to a central closing tube HI and braced thereto by webs I22. Central closing tube I2I is slidably mounted in the tubular guide sleeve Iilfi, and is threadably and rotatably secured by a lock nut IE4 at its upper end to a sheave block I25 having a pin I26 securing the closing tube sheave Bl.

Thus, actuation of the closing drum 34 by the operator will, thru closing line 96, draw up closing tube I2! within guide sleeve IIJEI, andby its central pull on the bucket legs H5 will close the.\

bucket shells H2 together with as much force as the power unit can supply. It should be noted that the direct pull of the winch on the closing line 96 is doubled by anchoring the line 96 to face plate I7 and passing it under sheave 97. The degree of opening permitted the bucket shells H2 is controlled by the position of a threaded collar I2! adjustably positioned on threaded portion I29 of closing tube IZI, which nut strikes against guide tube IfiIl as the bucket opens.

Staggered bucket teeth I38 are fixed to the bucket shells IIZ by suitable bolts I3I and may be replaced when necessary. It will be observed from Fig. 9 that when fully open, the outer surfaces I32 of the bucket teeth are vertical, so that the digging action produces a straight-sided hole.

Crowd yoke I 32 and crowd collar Hit are rotatable relative to each other, as is closing tube I2I relative to its block 525 and sheave 91, so. that the bucket may be turned to avoid obstacle and produce the desired square hole. A pin I32 is insertable thru. a crowd collar hole I34 into any one of four crowd yoke holes I35, permitting the bucket to be locked in four positions along two normal axes.

Returm'ng now to the showing of Fig. 1, the dump cart H, which may be of any form providing it has a low body which can be inserted under the bucket to receive its load and a wheel base wide enough to clear the hole, is used to aid in the analysis of the ore, by following a preferred procedure. Each load is dumped adjacent the previous load in a line and separated enough so that successive loads may be clearly differentiated.

Since the bucket capacity is a known constant, and a skilled operator can dig a full load each time, it will be apparent that the analyst can tell by observing the position of each pile of earth in the line, from what depth it was taken, and can tell the thickness as well as the character of each stratum.

From the above description, it will be seen that I have invented a machine for digging test holes and sampling ore which can be readily transportedfrom place to place with great speed. The machine is able to dig with speed surpassing that of any known core-digging tool and to any desired depth. It is not prevented from functioning by the presence of large rocks in its path, altho of course it can not be expected to go thru solid rock strata of thicknes sufiicient to require blasting. The operator is able to remove a sample large enough so that errors in analysis, commonly formed with small cores, may be minimized, Only two operators are required, one of whom may be unskilled.

Finally, the expense of operation over all is substantially less than in prior sampling operations, and mechanical upkeep and breakdowns are a minimum.

I claim:

1. In a digger, the combination of a vertical guide, a mast traversable therein, a bucket assembly movable relatively with respect to said mast, a bucket closing member slidably disposed within said mast and arranged to hold said bucket normally in open position, and supporting means for said bucket and for said bucket closing means arranged to permit rotation of said bucket and bucket closing means relative to said mast.

2. In a, digger, the combination of a supporting framework a vertically transversable mast guided in a portion of said frame-work, a bucket assembly with a rigid central stem rotatable with respect to the longitudinal axis of said mast and mounted thereon with suitable locks against rotation for unitary operation of said bucket assembly, means for driving said mast and said bucket when open as a unit into. the ground to be dug, means for closing said bucket, means for upwardly transversing said mast and aid bucket in closed position and means for opening said bucket.

3. In a mobile digger, the combination of a vehicle, a digger supporting structure mounted on said vehicle, an auxiliary power plant mounted on said vehicle, a vertically traversable mast guided for movement in a portion of said supporting structure, a clam shell type bucket assembly with a rigid central stem mounted for horizontal rotation on said mast and forming a unitary structure with said mast in the digging phase when in locked position, means for operating said mast and said bucket from said auxiliary power plant and means on said supporting structure for mounting said mast and said bucket assembly in a substantially horizontal position for mobility when not in use.

i. In a digger, in combination with a supportl ing framework and a vertically traversable mast guided in one portion of said framework, of a \clam shell type bucket assembly mounted for rotable change of position about the vertical axis at the lower end of said mast and means for locking said bucket assembly and holding the same to the mast for operation as a unitary structure in the digging operations.

5. In combination with a digger having a vertically slidable mast, of a crowd collar secured to the lower end of said mast, a crowd yoke for supporting the bucket assembly disposed adjacent to said crowd collar and rotatable with the central stem of the bucket assembly relative to said mast for changing the position of the bucket assembly, a bucket assembly comprising a clam shell type bucket with staggered teeth projecting from the lips thereof, arms pivotally mounted on said crowd yoke and said bucket shells arranged to produce a bucket opening tendency upon impact with the ground to be dug and a central rigid stem, and means for holding the bucket assembly against rotation on the mast during the digging operation.

6, The combination with a vehicle, of a portable digger comprising an auxiliary power plant anda mast guide fixed on said vehicle, a mast slidably disposed in said guide and controlled as to movement in operation by said auxiliary power plant, a bucket assembly mounted on the lowen end of said mast for change of position rotatably between bucket loads, means for carrying said mast and said bucket assembly in horizontal position on said vehicle when said digger not in operation, means for moving said mast and said bucket assembly from the horizontal position to a vertical position relative to said vehicle, means including a central rigid stem in the bucket assembly controllable by said auxiliary power plant for maintaining said bucket in normally open position and for rigidly resisting impacts in the digging operation.

'7. The combination with a vehicle, of a portable digger comprising an auxiliary power plant, a winch, and a mast guide fitted on said veir' ule, a mast slidably disposed in said guide and cmtrolled as to movement in o oration by said auxiliary power plant, a bucket assembly mounted at the lower end of said mast for change of position rotatably between bucket loads comprising a rigid central stem "for applying closing force centrally to said bucket, a split housing fixed to said closing force applying means, a shaft journaled in said housing and passing through said bucket centrally of the sides thereof, means for maintaining said housing together about the shaft, a pair of oppositely disposed bucket shells, digging teeth attached to said bucket shells and arranged in staggered fashion to intermesh and permit the lips of the bucket to meet when it is in closed position, said teeth being also arranged so that their outer surfaces are substantially vertical to the digging surface when the bucket is in open digging position.

8. In a bucket assembly adapted for vertical digging, the combination of oppositely disposed bucket shells, digging teeth on each of said bucket shells projecting beyond the lips thereof in staggered relation so to permit the lips of the bucket shells to meet when in closed position, a rigid central stem for centrally applying the digging force to the teeth and for applying the closing force centrally and linkage arms pivotally mounted between said bucket shells and the assembly supporting means assisting in delivering the digging force to the bucket teeth and arranged to produce a bucket opening tendency on impact of the assembly with the ground to be dug.

9. A bucket assembly as described cl 8 and means for adjusting the length of the central rigid stem so that the outer surface of the digging teeth on the bucket shells may always be directed substantially at right angles to the surface to be dug when the bucket assembly is in open digging position.

HERBERT G. STRAIN. 

